Kristianingrum, Susila, Endang Dwi Siswani, and Suyanta Suyanta. “MODIFICATION OF KELUD VOLCANIC ASH 2014 AS SELECTIVE ADSORBENT MATERIAL FOR COPPER(II) METAL ION”. Jurnal Sains Dasar 5, no. 1 (April 26, 2016): 7–16. Accessed May 10, 2025. https://journal.uny.ac.id/index.php/jsd/article/view/12659.